Power supply controller

Abstract

One aspect of the present invention is directed to a power supply controller that includes a switching element disposed between a power source and a load, a current detecting element connected to the switching element and capable of outputting a detection signal in the form of a load current to the switching element, a voltage generator circuit capable of supplying an output voltage between the switching element and the load, an anomaly detecting circuit capable of outputting an abnormal signal when the load current exceeds a threshold current such that the threshold current corresponds to the output voltage. The present invention can further include a protection circuit capable of performing a predetermined protection operation based on the abnormal signal, a control circuit capable of receiving an on signal and an off signal, wherein the control circuit turns on the switching element when receiving the on signal and turns off the switching element when receiving the off signal, and a blocking circuit capable of blocking the predetermined protection operation when the off signal is received.

1. A power supply controller, comprising:
 a switching element that is disposed between a power source and a load, the load being an inductive load; 
 a current detecting element that is connected in parallel to the switching element and outputs a detection signal corresponding to a load current that flows to the switching element; 
 a voltage generator circuit that generates a generation voltage that corresponds to an output voltage across the load; 
 an anomaly detecting circuit that, when a voltage corresponding to the detection signal exceeds the generation voltage, outputs an abnormal signal; 
 a protection circuit that performs a predetermined protection operation based on the abnormal signal that is outputted from the anomaly detecting circuit, the protection circuit forcing the switching element to shut off and be kept in a shutoff state for a predetermined reference shutoff time period, as the predetermined protection operation; 
 a control circuit into which an on signal and an off signal are inputted, and which turns on the switching element based on input of the on signal and turns off the switching element based on input of the off signal; and 
 a blocking circuit that blocks execution of the predetermined protection operation by the protection circuit when the off signal is inputted and the voltage corresponding to the detection signal exceeds the generation voltage. 
 
     
     
       2. The power supply controller according to  claim 1 ,
 wherein the blocking circuit has a configuration that, when the off signal is inputted, nullifies the abnormal signal from the anomaly detecting circuit to block execution of the protection operation by the protection circuit. 
 
     
     
       3. The power supply controller according to  claim 1 ,
 wherein the protection circuit has a configuration that, when the abnormal signal is outputted, after causing the switching element to perform a shutoff operation for a reference shutoff time period, turns on the switching element as the protection operation. 
 
     
     
       4. The power supply controller according to  claim 1 , wherein,
 the protection circuit comprises an anomaly time accumulating circuit that, when the abnormal signal is outputted, starts to accumulate an amount of anomaly time, and causes the switching element to perform a shutoff operation as the protection operation when the amount of anomaly time reaches a reference anomaly time, and 
 a normal time accumulating circuit that, after the anomaly time accumulating circuit starts to accumulate the amount of anomaly time, accumulates an amount of normal time in which the load current is continuously at or below a normal level that is less than the threshold current, and clears the amount of anomaly time of the anomaly time accumulating circuit when the amount of normal time reaches a reference normal time. 
 
     
     
       5. A power supply controller, comprising:
 a switching element that is disposed between a power source and a load the load being an inductive load; 
 a current detecting element that is connected in parallel to the switching element and is capable of outputting a detection signal in the form of a load current to the switching element; 
 a voltage generator circuit that is capable of generating a generation voltage that corresponds to an output voltage across the load; 
 an anomaly detecting circuit that is capable of outputting an abnormal signal when a voltage corresponding to the detection signal exceeds the generation voltage; 
 a protection circuit that is capable of performing a predetermined protection operation based on the abnormal signal that is outputted from the anomaly detecting circuit, the protection circuit forcing the switching element to shut off and be kept in a shutoff state for a predetermined reference shutoff time period, as the predetermined protection operation; 
 a control circuit that is capable of receiving an on signal and an off signal, wherein the control circuit turns on the switching element when receiving the on signal and turns off the switching element when receiving the off signal; and 
 a blocking circuit that is capable of blocking the predetermined protection operation when the off signal is received and the voltage corresponding to the detection signal exceeds the generation voltage. 
 
     
     
       6. The power supply controller according to  claim 5 , wherein the outputting of the abnormal signal from the anomaly detecting circuit is also based upon the detection signal. 
     
     
       7. The power supply controller according to  claim 5 , wherein when the off signal is received, the blocking circuit is capable of nullifying the abnormal signal to block execution of the predetermined protection operation. 
     
     
       8. The power supply controller according to  claim 5 , wherein when the abnormal signal is outputted, after causing the switching element to perform the shutoff operation for the reference shutoff time period, the protection circuit is capable of turning on the switching element. 
     
     
       9. The power supply controller according to  claim 5 , wherein the protection circuit includes an anomaly time accumulating circuit that starts to accumulate an amount of anomaly time when the abnormal signal is outputted. 
     
     
       10. The power supply controller according to  claim 9 , wherein the protection circuit causes the switching element to perform the shutoff operation as the protection operation when the amount of anomaly time reaches a reference anomaly time. 
     
     
       11. The power supply controller according to  claim 10 , further including a normal time accumulating circuit that, after the anomaly time accumulating circuit starts to accumulate the amount of anomaly time, accumulates an amount of normal time in which the load current is continuously at or below a normal level that is less than the output voltage. 
     
     
       12. The power supply controller according to  claim 11 , wherein the normal time accumulating circuit clears the amount of anomaly time of the anomaly time accumulating circuit when the amount of normal time reaches a reference normal time.